Need some advice as so far I am stumped!!

I have a '97 Z71 with the Vortec V8 5.7L. About a year ago my check engine light came on and soon thereafter began blinking. Was given codes for P0300 Random misfire, vacuum leak, and fuel running too rich.

Since then I have replaced the following: Intake gasket, distributor rotor and cap, spark plugs, new wires, all 02 sensors, PCM valve, fuel filter.

The vacuum leak is gone. I am still receiving the Random Misfires but you can still smell the gas running too rich. When checking the new plugs recently I realized they have gas on them. When changing the oil recently, a distinct gas odor is present as well as the level being higher. Also, a slight "knocking" noise coming from the heads has started.

Since all of the issues I have only rarely driven the truck and has pretty much been sitting since all of the repairs. My next fix will be the fuel pressure regulator but any ideas as to what else might be the issue?

Thanks in advance.